The present invention relates to a ball joint in general, and more particularly to a ball joint, which can be profitably used in the steering or wheel-suspending system of a motor vehicle.
Ball joints of this general type are already known and in widespread use, particularly in the motor vehicle manufacturing industry. Joints of this type must be so constructed as not to permit any play between the two members which together constitute the ball joint and one of which has a spherical mounting portion, and the other of which has a socket portion which bounds a spherical cavity that receives the spherical mounting portion of the above-mentioned member. On the other hand, the two members must be capable of moving relative to one another with relative ease. Until now, it has not been possible to satisfy both of these requirements in an ideal manner, without incurring extraordinarily high manufacturing expenses. Moreover, it has been established that, in order to improve the response of the ball joint of this type to forces acting on the movable member thereof, and thus to enhance the comfort of the ride in a vehicle equipped with a ball joint, or ball joints of this type, an additional requirement is to be met, namely that the pivotal movement of the movable member of the ball joint relative to the other member of the ball joint is to be easier, when the movable member pivotally moves about one axis of rotation, than when it moves about another axis of rotation.
In this latter connection, it has already been proposed, in U.S. Pat. No. 2,614,873, to so construct the ball joint, so that the mounting portion of one of the members thereof is apportioned and presents different contact surfaces subjected to loads or stresses of different magnitudes for the rotational movement, on the one hand, and for the pivotal movement, on the other hand. As a result of this, the rotational movement about the axis of the one member which has the mounting portion is made relatively easy, while the pivoting movement in all other directions is made more difficult. However, this conventional arrangement is rather complex, expensive, prone to malfunction, and subject to substantial wear, particularly in view of the fact that the separate contact surfaces of the mounting portion have relatively small areas.